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export class ColorService {
/**
* http://stackoverflow.com/questions/2353211/hsl-to-rgb-color-conversion
*
* Converts an HSL color value to RGB. Conversion formula
* adapted from http://en.wikipedia.org/wiki/HSL_color_space.
* Assumes h, s, and l are contained in the set [0, 1] and
* returns r, g, and b in the set [0, 255].
*
* @param Number h The hue
* @param Number s The saturation
* @param Number l The lightness
* @return Array The RGB representation
*/
hslToRgb(h, s, l) {
var r, g, b;
if (s == 0) {
r = g = b = l; // achromatic
} else {
function hue2rgb(p, q, t) {
if (t < 0) t += 1;
if (t > 1) t -= 1;
if (t < 1 / 6) return p + (q - p) * 6 * t;
if (t < 1 / 2) return q;
if (t < 2 / 3) return p + (q - p) * (2 / 3 - t) * 6;
return p;
}
var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
var p = 2 * l - q;
r = hue2rgb(p, q, h + 1 / 3);
g = hue2rgb(p, q, h);
b = hue2rgb(p, q, h - 1 / 3);
}
return [Math.floor(r * 255), Math.floor(g * 255), Math.floor(b * 255)];
}
// convert a number to a color using hsl
numberToColorHsl(i) {
// as the function expects a value between 0 and 1, and red = 0° and green = 120°
// we convert the input to the appropriate hue value
var hue = i * 100 * 1.2 / 360;
// we convert hsl to rgb (saturation 100%, lightness 50%)
var rgb = this.hslToRgb(hue, .9, .4);
// we format to css value and return
return 'rgb(' + rgb[0] + ',' + rgb[1] + ',' + rgb[2] + ')';
}
}
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